Dental flask



Feb. 6, I923.

M, F. BURNS. DENTAL FLASK. FILED MAR, 24,

INVENTOR @W ATTORNEY Kc BY Patented Feb. 6, 1223.

MARTIN E. BURNS, F ASTORIA, NEW YORK.

DENTAL FLASK.

Application filed March 24, 1922.

T 0 all whom it may concern:

Be it known that I, MARTIN F. BURNS, a citizen of the United States, and a resident of Astoria, county of Queens and State of New York, have invented certain new and useful Improvements in Dental Flasks, of which the following is a specification.

This invention relates to dental apparatus and more particularly to dental flasks of the type used by dentists in casting plates, bridges, inlays and other restorations.

In casting a plate, bridge or other restoration a dentist first makes a pattern in was of the article to be cast. The pattern is then invested in an initially plastic and quick hardening composition. When the investment is dry or has set the wax is melted out or otherwise dissipated, the cavity. is filled with molten metal. The casting is then allowed to 000-1 and is preferably cooled slowly to prevent warping or distortion. When warping or distortion takes place it is necessary to swage the casting to its proper shape.

As the investment used in the process above outlined is expensive, one of the objects of the invention is to provide apparatus of the class described that will require the use of a minimum amount of investment.

Another object of the invention is to provide means for slowly cooling the casting.

Further objects of the invention will appear from the following description taken in connection with the drawings which form a part of this application and in which,

Fig. l'is an exploded view showing the various parts of the apparatus constructed in accordance with the invention.

Fig. 2 is an elevation, partly in section of the parts in their assembled position.

Fig. 3 is a transverse sectional view taken substantially on line 3-3 of Fig. 2 and Fig. 4 is a vertical sectional view show ing another form of investment holder.

1 The invention may be briefly described as comprising an investment holder adapted to fit in a receptacle and having side walls spaced apart throughout their length and held in spaced position by connecting members. At one or both of the ends of the investment holder are formed flanges conforming in peripheral contour substantially to thejinner surface of the wall of the reat ceptacle. The receptacle has formedthere Serial No. 546,303.

in openings at both ends and in order to cool the casting slowly as hereinafter more fully explained, means is provided for sealing the ends of the receptacle.

Referring to the drawings I have shown a receptacle 10 having its upper end 11 open and its lower end provided with a central opening or aperture 12 formed by an inwardly extending flange 13. An annular downwardly extending rib 1a is formed at the inner periphery of the flange for a purpose hereinafter described. The wall of the receptacle 10 is preferably imperforate and cylindrical.

The investment holder 15 is adapted to fit in the receptacle 10 and has a pair of vertical, substantially parallel, flat, rectangular walls 16 and 17 connected at their upper and lower ends respectively by webs or strips 18 and 19. Laterally and outwardly extending flanges 20 are formed at the upper edges of the walls 16 and 17 and these fiangesare disposed in the plane of the webs or strips 18 and form a flat upper end for the investment holder. As shown in the drawings the strips 18 and flanges 20 have their outer peripheries disposed in a circle'slightly smaller in diameter than the inner diameter of the receptacle 10.

In Fig. 1 the flanges are shown at one end only of the investment holder but if desired such flanges may be formed at both ends as shown in Fig. 4 at 20 and 20'.

From the showing in Fig. 2 it will be seen that the investment holder rests on the flange 13 on the bottom of the receptacle and is so dimensioned that its upper edge will be spaced! slightly from the upper end of the receptacle 10. A cover plate 21 is adapted to fit over the upper end of the receptacle 10 and has formed thereon an outwardly extending cylindrical flange 22. The plate 21 also has formed therein a plurality of countersunk openings 23 through which the investment may pass. Because of the countersunk construction the investment will hold the cover plate in position on the receptacle 10.

In using the apparatus the dentist or operator will place in the investment holder 15 the wax pattern of the casting to be made. The holder is placed in the receptacle 10 and the cover 21 is placed on the receptacle. The casting is then invested in the plastic composition. and. because of the particular form or the holder a comparatively small amount of the investment is necessary. lVhen' the investment is set or hardened heat is applied to the sides or bot-tom of the receptacle and the wax forming the pattern is melted and dissipated. In this heating process the use of the flanges 20 at the lower end of the investment holder will effect a slower heating than can be eilected with the holder shown in Fig. 1.

When the war; has been melted, the mold is filled with molten metal and thereafter it is very desirable that the casting be cooled slowly in order to prevent possible warping or distortion.

In order to effect such a slow cooling of the casting I have provided means for sealing the upper and lower ends of the receptacle thereby confining therein the air which surrounds the investment holder. This is accomplished by a cap 80 having a lining 31 ot'asbestos or similar material and also by a cap 32 and a lining 83. The cap 30 is placed over the flange 14 at the bottom. of

the receptacle 10 and the cap 32 is placed over the upper edge oi the annular flange 22 formed on the cover plate 21. It will be readily understood that by reason of the sealing of the receptacle the casting will be cooled slowly.

The size and nature of the casting to be made will determine the proper form of investment holder to be used. For instance, in very thin castings a much slower cooling is required or at least is desirable than is the case with heavier or thicker castings. The holder shown in Fig. 4 will give both a slower heating and a slower cooling effect than will the holder shown in Fig. 1. Also the use of the caps for obtaining a slower cooling is not as necessary with the form of holder shown in Fig. 45 as with the other form.

Although certain specific embodiments of the invention have been illustrated and de scribed it will be understood that the invention is capable of further modification and that further changes in the construction and in the arrangement of the various cooperating parts may be made without departing from the spirit or scope of the invention as expressed in the following claims.

Vihat I claim is 1. An investment holder having open ends and comprising a pair of flat spaced plates, connecting strips for holding the plates in spaced relation and flanges extending outwardly from at least one end of the plates. 2. An investment holder comprising a pair of flat, spaced plates, connecting means for holding the'plates in spaced relation and outwardly extendingflanges formed at the opposite ends of each plate.

'3. In combination, a receptacle, an investment holder, comprising a pair of flat,

'ing in the cover plate.)

spaced, rectangular plates, connecting means for holding the plates in spaced relation and flanges extending outwardly from at least one end. of the plates and adapted to coact with the-wall oi' the receptacle to position 7") the investment holder therein.

-l. i-in investment holder having open ends and comprising a pair of flat, substantially parallel, spaced plates, connecting means for holding the plates in spaced relation and substantially flat flanges extending outwardly from at least one end of the plates.

5. Apparatus oil the character described comprising a substantially cylindrical receptacle having a vertical wall and an apertured bottom and an investment holder having a pair of spaced apart, straight, vertical walls and flanges extending laterally from the upper edges therefor and fitting within the cylindrical wall of the receptacle.

6. Apparatus of the character described comprising a receptacle, an investment holder adapted to be positioned therein and having a pair of spaced vertical walls, con nected together and a flat upper end formed by the connecting means and laterally and outwardly extending flanges at the upper edges of the vertical wall 7. Apparatus of the character described comprising a receptacle, an investment holder adapted to be positioned thereon and having a pair of spaced vertical walls, connected together, and a flat upper end formed by the connecting means and laterally and outwardly extending flanges at the upper edges of the vertical walls, the flat upper end of the holder conforming inperipheral contour to the inner surface oi"? the receptacle wall.

8. In combination, a receptacle, having openings at both ends thereoflan investment holder adapted to be positioned therein, and impervious means for closing and sealing both end openings of'the receptacle.

9. In combination, a receptacle, having openings at both ends thereof, an investment holder adapted to be positioned therein and have its walls spaced from the receptacle wall, and impervious means for closing and sealing both end openings of the receptacle.

10. In combination, a. receptacle having an apertured bottom and opennpper end, an apertured cover for the upper end, an investment holder adapted to fit in said receptacle, and impervious means for sealing the apertured bottom and the opening in the cover plate.

11. In combination, a receptacle having an apertured bottom and open upper end, an apertured cover for the upper end, an in-12 vestment holder adapted to fit in said receptacle, and having its walls spaced from the l receptacle wall, and impervious means for l sealing the apertured bottom and the :openl 12. In combination, a receptacle having a bottom provided with a central aperture and having an open upper end, and an investment holder adapted to lit in said receptacle having a portion conforming in shape to the inner periphery of the receptacle and having vertical spaced, substantially parallel walls.

13. In combination, a receptacle having a bottom provided with a central aperture and having an open upper end and an investment holder adapted to fit in said receptacle, having end portions conforming in shape to the inner periphery of the receptacle and having vertical, spaced, substantially parallel walls.

14:. An investment holder comprising pair of fiat, spaced, iniperforate plates, con-- necting means for holding the plates in spaced relation and outwardly extending flanges formed at the opposite ends of each plate.

15. An investment holder comprising a pair of flat, spaced, imperforate plates, connecting means for holding the plates in spaced relation and flanges extending out Wardly from at least one end of the plates.

In Witness whereof, I have hereunto set my hand this 22 day of-March, 1922.

MARTIN F. BURNS, 

